title: MicroRNA profiles classify papillary renal cell carcinoma subtypes.
abstract: BACKGROUND
  Besides the conventional clear-cell renal cell carcinoma (ccRCC), papillary RCC (pRCC) is the second most common renal malignancy. Papillary RCCs can further be subdivided into two distinct subtypes. Although a clinical relevance of pRCC subtyping has been shown, little is known about the molecular characteristics of both pRCC subtypes.
  
  
  METHODS
  We performed microarray-based microRNA (miRNA) expression profiling of primary ccRCC and pRCC cases. A subset of miRNAs was identified and used to establish a classification model for ccRCC, pRCC types 1 and 2 and normal tissue. Furthermore, we performed gene set enrichment analysis with the predicted miRNA target genes.
  
  
  RESULTS
  Only five miRNAs (miR-145, -200c, -210, -502-3p and let-7c) were sufficient to identify the samples with high accuracy. In a collection of 111 tissue samples, 73.9% were classified correctly. An enrichment of miRNA target genes in the family of multidrug-resistance proteins was noted in all tumours. Several components of the Jak-STAT signalling pathway might be targets for miRNAs that define pRCC tumour subtypes.
  
  
  CONCLUSIONS
  MicroRNAs are able to accurately classify RCC samples. Deregulated miRNAs might contribute to the high chemotherapy resistance of RCC. Furthermore, our results indicate that pRCC type 2 tumours could be dependent on oncogenic MYC signalling.
authors.affiliation: Department of Urology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany. sven.wach@uk-erlangen.de
authors.forename: S
authors.initials: S
authors.lastname: Wach
authors.forename: E
authors.initials: E
authors.lastname: Nolte
authors.forename: A
authors.initials: A
authors.lastname: Theil
authors.forename: C
authors.initials: C
authors.lastname: Stöhr
authors.forename: T
authors.initials: T
authors.lastname: T Rau
authors.forename: A
authors.initials: A
authors.lastname: Hartmann
authors.forename: A
authors.initials: A
authors.lastname: Ekici
authors.forename: B
authors.initials: B
authors.lastname: Keck
authors.forename: H
authors.initials: H
authors.lastname: Taubert
authors.forename: B
authors.initials: B
authors.lastname: Wullich
mesh_terms: D002292:Carcinoma, Renal Cell / Q000145:classification / Q000235:genetics* / Q000473:pathology; D015331:Cohort Studies; D020869:Gene Expression Profiling; D006801:Humans; D007680:Kidney Neoplasms / Q000145:classification / Q000235:genetics* / Q000473:pathology; D035683:MicroRNAs / Q000096:biosynthesis / Q000235:genetics*; D025341:Principal Component Analysis
chemical_list: D035683:MicroRNAs